STAT 100A Lecture Notes - Lecture 7: Probability Mass Function, Random Variable, Sample Space
Document Summary
De nition the sample space to the real line is called a random variable. (random variable). A function x : r which maps points from. Three balls are to be randomly selected, without replacement, from an urn contain- ing 20 balls numbered 1 to 20. Therefore, x is a random variable which has a value from {3, . Let the value of the highest valued ball be i. Therefore, the number of ways to select the remaining two balls is i 1c2. Therefore, the probability of the value of the highest valued ball being i is. P(x 17) = p(x = 17) + p(x = 18) + p(x = 19) + p(x = 20) A random variable that can have at most a countable number of possible values is said to be discrete. A function which gives the probability of a discrete random variable x having value x is called the probability mass function of x.
